Interference cancellation in a spread spectrum communication system

ABSTRACT

A code division multiple access communication system transmits a pilot and traffic signal over a shared spectrum. The pilot and traffic signal have an associated code. Signals are received over the shared spectrum. The received signals are sampled. The samples are delayed to produce a window. The window has evenly time spaced samples. Each window sample is despread with a pilot code. A weight for each despread pilot code window sample is determined using an adaptive algorithm. Each window sample is despread with a traffic code. Each despread traffic code window sample is weighted with a corresponding weight of the determined weights. The despread traffic code window sample are combined as data of the traffic signal.

This application is a continuation of application Ser. No. 09/892,369,filed Jun. 27, 2001 now abandoned, which is a continuation ofapplication Ser. No. 09/659,858, filed Sep. 11, 2000, now U.S. Pat. No.6,278,726, which is a continuation-in-part of application Ser. No.09/602,963, filed Jun. 23, 2000, now U.S. Pat. No. 6,373,877 which is acontinuation of application Ser. No. 09/394,452, filed Sep. 10, 1999,now U.S. Pat. No. 6,115,406.

BACKGROUND

The present invention relates generally to signal transmission andreception in a wireless code division multiple access (CDMA)communication system. More specifically, the invention relates toreception of signals to reduce interference in a wireless CDMAcommunication system.

A prior art CDMA communication system is shown in FIG. 1. Thecommunication system has a plurality of base stations 20-32. Each basestation 20 communicates using spread spectrum CDMA with user equipment(UEs) 34-38 within its operating area. Communications from the basestation 20 to each UE 34-38 are referred to as downlink communicationsand communications from each UE 34-38 to the base station 20 arereferred to as uplink communications.

Shown in FIG. 2 is a simplified CDMA transmitter and receiver. A datasignal having a given bandwidth is mixed by a mixer 40 with a pseudorandom chip code sequence producing a digital spread spectrum signal fortransmission by an antenna 42. Upon reception at an antenna 44, the datais reproduced after correlation at a mixer 46 with the same pseudorandom chip code sequence used to transmit the data. By using differentpseudo random chip code sequences, many data signals use the samechannel bandwidth. In particular, a base station 20 will communicatesignals to multiple UEs 34-38 over the same bandwidth.

For timing synchronization with a receiver, an unmodulated pilot signalis used. The pilot signal allows respective receivers to synchronizewith a given transmitter allowing despreading of a data signal at thereceiver. In a typical CDMA system, each base station 20 sends a uniquepilot signal received by all UEs 34-38 within communicating range tosynchronize forward link transmissions. Conversely, in some CDMAsystems, for example in the B-CDMATM air interface, each UE 34-38transmits a unique assigned pilot signal to synchronize reverse linktransmissions.

When a UE 34-36 or a base station 20-32 is receiving a specific signal,all the other signals within the same bandwidth are noise-like inrelation to the specific signal. Increasing the power level of onesignal degrades all other signals within the same bandwidth. However,reducing the power level too far results in an undesirable receivedsignal quality. One indicator used to measure the received signalquality is the signal to noise ratio (SNR). At the receiver, themagnitude of the desired received signal is compared to the magnitude ofthe received noise. The data within a transmitted signal received with ahigh SNR is readily recovered at the receiver. A low SNR leads to lossof data.

To maintain a desired signal to noise ratio at the minimum transmissionpower level, most CDMA systems utilize some form of adaptive powercontrol. By minimizing the transmission power, the noise between signalswithin the same bandwidth is reduced. Accordingly, the maximum number ofsignals received at the desired signal to noise ratio within the samebandwidth is increased.

Although adaptive power control reduces interference between signals inthe same bandwidth, interference still exists limiting the capacity ofthe system. One technique for increasing the number of signals using thesame radio frequency (RF) spectrum is to use sectorization. Insectorization, a base station uses directional antennas to divide thebase station's operating area into a number of sectors. As a result,interference between signals in differing sectors is reduced. However,signals within the same bandwidth within the same sector interfere withone another. Additionally, sectorized base stations commonly assigndifferent frequencies to adjoining sectors decreasing the spectralefficiency for a given frequency bandwidth. Accordingly, there exists aneed for a system which further improves the signal quality of receivedsignals without increasing transmitter power levels.

SUMMARY

A code division multiple access communication system transmits a pilotand traffic signal over a shared spectrum. The pilot and traffic signalhave an associated code. Signals are received over the shared spectrum.The received signals are sampled. The samples are delayed to produce awindow. The window has evenly time spaced samples. Each window sample isdespread with a pilot code. A weight for each despread pilot code windowsample is determined using an adaptive algorithm. Each window sample isdespread with a traffic code. Each despread traffic code window sampleis weighted with a corresponding weight of the determined weights. Thedespread traffic code window samples are combined as data of the trafficsignal.

BRIEF DESCRIPTION OF THE DRAWING(S)

FIG. 1 is a prior art wireless spread spectrum CDMA communicationsystem.

FIG. 2 is a prior art spread spectrum CDMA transmitter and receiver.

FIG. 3 is the transmitter of the invention.

FIG. 4 is the transmitter of the invention transmitting multiple datasignals.

FIG. 5 is the pilot signal receiving circuit of the invention.

FIG. 6 is the data signal receiving circuit of the invention.

FIG. 7 is an embodiment of the pilot signal receiving circuit.

FIG. 8 is a least mean squared weighting circuit.

FIG. 9 is the data signal receiving circuit used with the pilot signalreceiving circuit of FIG. 7.

FIG. 10 is an embodiment of the pilot signal receiving circuit where theoutput of each RAKE is weighted.

FIG. 11 is the data signal receiving circuit used with the pilot signalreceiving circuit of FIG. 10.

FIG. 12 is an embodiment of the pilot signal receiving circuit where theantennas of the transmitting array are closely spaced.

FIG. 13 is the data signal receiving circuit used with the pilot signalreceiving circuit of FIG. 12.

FIG. 14 is an illustration of beam steering in a CDMA communicationsystem.

FIG. 15 is a beam steering transmitter.

FIG. 16 is a beam steering transmitter transmitting multiple datasignals.

FIG. 17 is the data receiving circuit used with the transmitter of FIG.14.

FIG. 18 is a pilot signal receiving circuit used when uplink anddownlink signals use the same frequency.

FIG. 19 is a transmitting circuit used with the pilot signal receivingcircuit of FIG. 18.

FIG. 20 is a data signal receiving circuit used with the pilot signalreceiving circuit of FIG. 18.

FIG. 21 is a simplified receiver for reducing interference.

FIG. 22 is an illustration of a vector correlator/adaptive algorithmblock using a least mean square error algorithm.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The preferred embodiments will be described with reference to thedrawing figures where like numerals represent like elements throughout.FIG. 3 is a transmitter of the invention. The transmitter has an arrayof antennas 48-52, preferably 3 or 4 antennas. For use in distinguishingeach antenna 48-52, a different signal is associated with each antenna56-60. The preferred signal to associate with each antenna is a pilotsignal as shown in FIG. 3. Each spread pilot signal is generated by apilot signal generator 56-60 using a different pseudo random chip codesequence and is combined by combiners 62-66 with the respective spreaddata signal. Each spread data signal is generated using data signalgenerator 54 by mixing at mixers 378-382 the generated data signal witha different pseudo random chip code sequence per antenna 48-52, D1-DN.The combined signals are modulated to a desired carrier frequency andradiated through the antennas 48-52 of the array.

By using an antenna array, the transmitter utilizes spacial diversity.If spaced far enough apart, the signals radiated by each antenna 48-52will experience different multipath distortion while traveling to agiven receiver. Since each signal sent by an antenna 48-52 will followmultiple paths to a given receiver, each received signal will have manymultipath components. These components create a virtual communicationchannel between each antenna 48-52 of the transmitter and the receiver.Effectively, when signals transmitted by one antenna 48-52 over avirtual channel to a given receiver are fading, signals from the otherantennas 48-52 are used to maintain a high received SNR. This effect isachieved by the adaptive combining of the transmitted signals at thereceiver.

FIG. 4 shows the transmitter as used in a base station 20 to sendmultiple data signals. Each spread data signal is generated by mixing atmixers 360-376 a corresponding data signal from generators 74-78 withdiffering pseudo random chip code sequences D11-DNM. Accordingly, eachdata signal is spread using a different pseudo random chip code sequenceper antenna 48-52, totaling N×M code sequences. N is the number ofantennas and M is the number of data signals. Subsequently, each spreaddata signal is combined with the spread pilot signal associated with theantenna 48-52. The combined signals are modulated and radiated by theantennas 48-52 of the array.

The pilot signal receiving circuit is shown in FIG. 5. Each of thetransmitted pilot signals is received by the antenna 80. For each pilotsignal, a despreading device, such as a RAKE 82-86 as shown in the FIG.5 or a vector correlator, is used to despread each pilot signal using areplica of the corresponding pilot signal's pseudo random chip codesequence. The despreading device also compensates for multipath in thecommunication channel. Each of the recovered pilot signals is weightedby a weighting device 88-92. Weight refers to both magnitude and phaseof the signal. Although the weighting is shown as being coupled to aRAKE, the weighting device preferably also weights each finger of theRAKE. After weighting, all of the weighted recovered pilot signals arecombined in a combiner 94. Using an error signal generator 98, anestimate of the pilot signal provided by the weighted combination isused to create an error signal. Based on the error signal, the weightsof each weighting device 88-92 are adjusted to minimize the error signalusing an adaptive algorithm, such as least mean squared (LMS) orrecursive least squares (RLS). As a result, the signal quality of thecombined signal is maximized.

FIG. 6 depicts a data signal receiving circuit using the weightsdetermined by the pilot signal recovery circuit. The transmitted datasignal is recovered by the antenna 80. For each antenna 48-52 of thetransmitting array, the weights from a corresponding despreading device,shown as a RAKE 82-86, are used to filter the data signal using areplica of the data signal's spreading code used for the correspondingtransmitting antenna. Using the determined weights for each antenna'spilot signal, each weighting device 106-110 weights the RAKE's despreadsignal with the weight associated with the corresponding pilot. Forinstance, the weighting device 88 corresponds to the transmittingantenna 48 for pilot signal 1. The weight determined by the pilot RAKE82 for pilot signal 1 is also applied at the weighting device 106 ofFIG. 6. Additionally, if the weights of the RAKE's fingers were adjustedfor the corresponding pilots signal's RAKE 82-86, the same weights willbe applied to the fingers of the data signal's RAKE 100-104. Afterweighting, the weighted signals are combined by the combiner 112 torecover the original data signal.

By using the same weights for the data signal as used with eachantenna's pilot signal, each RAKE 82-86 compensates for the channeldistortion experienced by each antenna's signals. As a result, the datasignal receiving circuit optimizes the data signals reception over eachvirtual channel. By optimally combining each virtual channel's optimizedsignal, the received data signal's signal quality is increased.

FIG. 7 shows an embodiment of the pilot signal recovery circuit. Each ofthe transmitted pilots are recovered by the receiver's antenna 80. Todespread each of the pilots, each RAKE 82-86 utilizes a replica of thecorresponding pilot's pseudo random chip code sequence, P1-PN. Delayedversions of each pilot signal are produced by delay devices 114-124.Each delayed version is mixed by a mixer 126-142 with the receivedsignal. The mixed signals pass through sum and dump circuits 424-440 andare weighted using mixers 144-160 by an amount determined by the weightadjustment device 170. The weighted multipath components for each pilotare combined by a combiner 162-164. Each pilot's combined output iscombined by a combiner 94. Since a pilot signal has no data, thecombined pilot signal should have a value of 1+j0. The combined pilotsignal is compared to the ideal value, 1+j0, at a subtractor 168. Basedon the deviation of the combined pilot signal from the ideal, the weightof the weighting devices 144-160 are adjusted using an adaptivealgorithm by the weight adjustment device 170.

A LMS algorithm used for generating a weight is shown in FIG. 8. Theoutput of the subtractor 168 is multiplied using a mixer 172 with thecorresponding despread delayed version of the pilot. The multipliedresult is amplified by an amplifier 174 and integrated by an integrator176. The integrated result is used to weight, W1M, the RAKE finger.

The data receiving circuit used with the embodiment of FIG. 7 is showfor a base station receiver in FIG. 9. The received signal is sent to aset of RAKEs 100-104 respectively associated with each antenna 48-52 ofthe array. Each RAKE 100-104, produces delayed versions of the receivedsignal using delay devices 178-188. The delayed versions are weightedusing mixers 190-206 based on the weights determined for thecorresponding antenna's pilot signal. The weighted data signals for agiven RAKE 100-104 are combined by a combiner 208-212. One combiner208-212 is associated with each of the N transmitting antennas 48-52.Each combined signal is despread M times by mixing at a mixer 214-230the combined signal with a replica of the spreading codes used forproducing the M spread data signals at the transmitter, D11-DNM. Eachdespread data signal passes through a sum and dump circuit 232-248. Foreach data signal, the results of the corresponding sum and dump circuitsare combined by a combiner 250-254 to recover each data signal.

Another pilot signal receiving circuit is shown in FIG. 10. Thedespreading circuits 82-86 of this receiving circuit are the same asFIG. 7. The output of each RAKE 82-86 is weighted using a mixer 256-260prior to combining the despread pilot signals. After combining, thecombined pilot signal is compared to the ideal value and the result ofthe comparison is used to adjust the weight of each RAKE's output usingan adaptive algorithm. To adjust the weights within each RAKE 82-86, theoutput of each RAKE 82-86 is compared to the ideal value using asubtractor 262-266. Based on the result of the comparison, the weight ofeach weighting device 144-160 is determined by the weight adjustmentdevices 268-272.

The data signal receiving circuit used with the embodiment of FIG. 10 isshown in FIG. 11. This circuit is similar to the data signal receivingcircuit of FIG. 9 with the addition of mixers 274-290 for weighting theoutput of each sum and dump circuit 232-248. The output of each sum anddump circuit 232-248 is weighted by the same amount as the correspondingpilot's RAKE 82-86 was weighted. Alternatively, the output of eachRAKE's combiner 208-212 may be weighted prior to mixing by the mixers214-230 by the amount of the corresponding pilot's RAKE 82-86 in lieu ofweighting after mixing.

If the spacing of the antennas 48-52 in the transmitting array is small,each antenna's signals will experience a similar multipath environment.In such cases, the pilot receiving circuit of FIG. 12 may be utilized.The weights for a selected one of the pilot signals are determined inthe same manner as in FIG. 10. However, since each pilot travels throughthe same virtual channel, to simplify the circuit, the same weights areused for despreading the other pilot signals. Delay devices 292-294produce delayed versions of the received signal. Each delayed version isweighted by a mixer 296-300 by the same weight as the correspondingdelayed version of the selected pilot signal was weighted. The outputsof the weighting devices are combined by a combiner 302. The combinedsignal is despread using replicas of the pilot signals' pseudo randomchip code sequences, P2-Pn, by the mixers 304-306. The output of eachpilot's mixer 304-306 is passed through a sum and dump circuit 308-310.In the same manner as FIG. 10, each despread pilot is weighted andcombined.

The data signal recovery circuit used with the embodiment of FIG. 12 isshown in FIG. 13. Delay devices 178-180 produce delayed versions of thereceived signal. Each delayed version is weighted using a mixer 190-194by the same weight as used by the pilot signals in FIG. 12. The outputsof the mixers are combined by a combiner 208. The output of the combiner208 is inputted to each data signal despreader of FIG. 13.

The invention also provides a technique for adaptive beam steering asillustrated in FIG. 14. Each signal sent by the antenna array willconstructively and destructively interfere in a pattern based on theweights provided each antenna 48-52 of the array. As a result, byselecting the appropriate weights, the beam 312-316 of the antenna arrayis directed in a desired direction.

FIG. 15 shows the beam steering transmitting circuit. The circuit issimilar to the circuit of FIG. 3 with the addition of weighting devices318-322. A target receiver will receive the pilot signals transmitted bythe array. Using the pilot signal receiving circuit of FIG. 5, thetarget receiver determines the weights for adjusting the output of eachpilot's RAKE. These weights are also sent to the transmitter, such as byusing a signaling channel. These weights are applied to the spread datasignal as shown in FIG. 15. For each antenna, the spread data signal isgiven a weight by the weighting devices 318-322 corresponding to theweight used for adjusting the antenna's pilot signal at the targetreceiver providing spatial gain. As a result, the radiated data signalwill be focused towards the target receiver. FIG. 16 shows the beamsteering transmitter as used in a base station sending multiple datasignals to differing target receivers. The weights received by thetarget receiver are applied to the corresponding data signals byweighting devices 324-340.

FIG. 17 depicts the data signal receiving circuit for the beam steeringtransmitter of FIGS. 15 and 16. Since the transmitted signal has alreadybeen weighted, the data signal receiving circuit does not require theweighting devices 106-110 of FIG. 6.

The advantage of the invention's beam steering are two-fold. Thetransmitted data signal is focused toward the target receiver improvingthe signal quality of the received signal. Conversely, the signal isfocused away from other receivers reducing interference to theirsignals. Due to both of these factors, the capacity of a system usingthe invention's beam steering is increased. Additionally, due to theadaptive algorithm used by the pilot signal receiving circuitry, theweights are dynamically adjusted. By adjusting the weights, a datasignal's beam will dynamically respond to a moving receiver ortransmitter as well as to changes in the multipath environment.

In a system using the same frequency for downlink and uplink signals,such as time division duplex (TDD), an alternate embodiment is used. Dueto reciprocity, downlink signals experience the same multipathenvironment as uplink signals send over the same frequency. To takeadvantage of reciprocity, the weights determined by the base station'sreceiver are applied to the base station's transmitter. In such asystem, the base station's receiving circuit of FIG. 18 is co-located,such as within a base station, with the transmitting circuit of FIG. 19.

In the receiving circuit of FIG. 18, each antenna 48-52 receives arespective pilot signal sent by the UE. Each pilot is filtered by a RAKE406-410 and weighted by a weighting device 412-416. The weighted andfiltered pilot signals are combined by a combiner 418. Using the errorsignal generator 420 and the weight adjustment device 422, the weightsassociated with the weighting devices 412-416 are adjusted using anadaptive algorithm.

The transmitting circuit of FIG. 19 has a data signal generator 342 togenerate a data signal. The data signal is spread using mixer 384. Thespread data signal is weighted by weighting devices 344-348 as weredetermined by the receiving circuit of FIG. 19 for each virtual channel.

The circuit of FIG. 20 is used as a data signal receiving circuit at thebase station. The transmitted data signal is received by the multipleantennas 48-52. A data RAKE 392-396 is coupled to each antenna 48-52 tofilter the data signal. The filtered data signals are weighted byweighting devices 398-402 by the weights determined for thecorresponding antenna's received pilot and are combined at combiner 404to recover the data signal. Since the transmitter circuit of FIG. 19transmits the data signal with the optimum weights, the recovered datasignal at the UE will have a higher signal quality than provided by theprior art.

An adaptive algorithm can also be used to reduce interference inreceived signals for a spread spectrum communication system. Atransmitter in the communication system, which can be located in eithera base station 20 to 32 or UE 34 to 36, transmits a spread pilot signaland a traffic signal over the same frequency spectrum. The pilot signalis spread using a pilot code, P, and the traffic signal is spread usinga traffic code, C.

The simplified receiver 500 of FIG. 21 receives both the pilot andtraffic signals using an antenna 502. The received signals aredemodulated to a baseband signal by a demodulator 518. The basebandsignal is converted into digital samples, such as by two analog todigital converters (ADC) 512, 514. Each ADC 512, 514 typically samplesat the chip rate. To obtain a half-chip resolution, one ADC 514 isdelayed with respect to the other ADC 512 by a one-half chip delay. Thesamples are processed by a filtering device, such two vector correlators504, 508 as shown in FIG. 21 or a RAKE, to process the pilot signal. Thevector correlators 504, 508, are used to despread various multipathcomponents of the received pilot signal using the pilot code, P. Byusing two vector correlators 504, 508 as in FIG. 21, each half-chipcomponent is despread, such as for a 10 chip window to despread 21components. Each despread component is sent to an adaptive algorithmblock 506 to determine an optimum weight for each despread component tominimize interference in the received pilot signal. The adaptivealgorithm block 506 may use a minimum mean square error (MMSE) algorithmsuch as a least mean square error algorithm.

One combination vector correlator/adaptive algorithm block using a LMSalgorithm and half-chip resolution is shown in FIG. 22. The pilot codeis delayed by a group of delay devices 5201 to 520N and 5221 to 522N.Each of the ADC samples is despread such as by mixing it with timedversions of the pilot code, P, by mixers 5241 to 524N and 5261 to 526N.The mixed signals are processed by sum and dump circuits 5281 to 528Nand 5301 to 530N to produce despread components of the pilot signal. Byusing two ADCs 512, 514 with a half-chip sampling delay and two vectorcorrelators 504, 508, despread components at half-chip intervals areproduced such as 21 components for a 10 chip window. Each despreadversion is weighted by a weight, W11 to W2N, such as by using aweighting device, 5441 to 544N and 5461 to 546N. The weighted versionsare combined, such as by using a summer 528. The combined signal iscompared to the complex transmitted value of pilot signal, such as 1+jfor a pilot signal in the third generation wireless standard, to producean error signal, e. The comparison may be performed by a subtractor 550by subtracting the combined signal from the ideal, 1+j. The errorsignal, e, is mixed using mixers 5321 to 532N and 5341 to 534N with eachdespread version. Each mixed version is amplified and integrated, suchas by using an amplifier 5361 to 536N and 5381 to 538N and an integrator5401 to 540N and 5421 to 542N. The amplified and integrated results arerefined weights, W11 to W2N, for further weighting of the despreadversions. Using the least mean square algorithm, the weights, W11 toW2N, will be selected as to drive the combined signal to its idealvalue.

The received signal is also processed by an adaptive filter 510 with theweights, W11 to W2N, determined for the pilot signal components. Sincethe pilot signal and the traffic signal are transmitted over the samefrequency spectrum, the two signals experience the same channelcharacteristics. As a result, the pilot weights, W11 to W2N, applied tothe traffic signal components reduces interference in the receivedtraffic signal. Additionally, if the pilot and channel signals were sentusing orthogonal spreading codes, the orthogonality of the receivedchannel signal is restored after weighting. The restored orthogonalitysubstantially reduces correlated interference from other trafficchannels that occurs as a result of the deorthogonalization due tochannel distortion. The weighted received signal is despread by atraffic despreader 516 using the corresponding traffic code to recoverthe traffic data.

What is claimed is:
 1. A method for receiving a traffic signal in a codedivision multiple access communication system, the system transmitting atraffic signal over a shared spectrum, traffic signal having anassociated code, the method comprising: receiving signals over theshared spectrum; sampling the received signals to produce samples;delaying the samples to produce a window, the window having evenly timespaced samples; despreading the samples and determining a weight foreach despread window sample using an adaptive algorithm, the adaptivealgorithm providing a determination of an optimum weight for each of aplurality of despread components; and adaptively filtering the receivedsignals using the associated code of the traffic signal and thedetermined weights to produce data of the traffic signal.
 2. The methodof claim 1 comprising: the system transmitting a reference signal andthe traffic signal over a shared spectrum, the reference signal havingan associated reference code; and despreading each window sample withthe reference code so that the determining of the weight for each windowprovides an optimum weight for each of a plurality of despreadcomponents with the reference signal.
 3. The method of claim 2 whereinthe reference signal includes a pilot signal and the reference codeincludes a pilot code.
 4. The method of claim 2 wherein the adaptivealgorithm comprises comparing a combination of the despread referencecode window samples with an ideal value to produce an error signal andusing the error signal to determine the weight for each despreadreference code window sample.
 5. The method of claim 1 comprising: thesystem transmitting a pilot signal and the traffic signal over a sharedspectrum, the pilot signal having an associated pilot code; anddespreading each window sample with the pilot code so that thedetermining of the weight for each window provides an optimum weight foreach of a plurality of despread components with the pilot signal,wherein the adaptive algorithm comprises comparing a combination of thedespread pilot code window samples with an ideal value to produce anerror signal and using the error signal to determine the weight for eachdespread pilot code window sample.
 6. The method of claim 5 wherein theideal value is 1+j.
 7. The method of claim 1 wherein the adaptivealgorithm is a minimum mean square error algorithm.
 8. The method ofclaim 1 wherein the adaptive algorithm is a least mean square erroralgorithm.
 9. The method of claim 1 wherein the evenly spaced samplesare evenly spaced at half chip intervals.
 10. A user equipment for usein code division multiple access communication system, the system havinga base station transmitting traffic signal over a shared spectrum, thetraffic signal having an associated code, the user equipment comprising:means for receiving signals over the shared spectrum; means for samplingthe received signals to produce samples; means for despreading thesamples and delaying the samples to produce a window, the window havingevenly time spaced samples; means for determining a weight for eachdespread window sample using an adaptive algorithm, the adaptivealgorithm providing a determination of an optimum weight for each of aplurality of despread components; means for adaptively filtering thereceived signals using the associated code of the traffic signal and thedetermined weights to produce data of the traffic signal.
 11. The userequipment of claim 10 wherein: the base station transmits a referenceand traffic signal over the shared spectrum, the reference and trafficsignal having an associated reference code; and the means fordetermining the weight of each window sample provides an optimum weightfor each of a plurality of despread components with the referencesignal.
 12. The user equipment of claim 11 wherein the reference signalincludes a pilot signal and the reference code includes a pilot code.13. The user equipment of claim 11 wherein the adaptive algorithmcomprises comparing a combination of the despread reference code windowsamples with an ideal value to produce an error signal and using theerror signal to determine the weight for each despread reference codewindow sample.
 14. The user equipment of claim 10 wherein: the basestation transmits a pilot and traffic signal over the shared spectrum,the pilot and traffic signal having an associated pilot code, thedespread window including the pilot code; and the means for determiningthe weight of each window sample provides an optimum weight for each ofa plurality of despread components with the pilot signal, wherein theadaptive algorithm comprises comparing a combination of the despreadpilot code window samples with an ideal value to produce an error signaland using the error signal to determine the weight for each despreadpilot code window sample.
 15. The user equipment of claim 14 wherein theideal value is 1+j.
 16. The user equipment of claim 10 wherein theadaptive algorithm is a minimum mean square error algorithm.
 17. Theuser equipment of claim 10 wherein the adaptive algorithm is a leastmean square error algorithm.
 18. The user equipment of claim 10 whereinthe evenly spaced samples are evenly spaced at half chip intervals.